Valve mechanism for fluid pressure tools



Oct. 17, 1933. E. w. STEVENS VALVE IECHANISI FOR FLUID PRESSURE TOOLS Filed Dec. 2'7, 1929 All.

JNVENTOR. Edward W Sfevens A TTORNEY.

Patented Oct. 17,1933 1 g V 4. 1,931,040

. 7 1,931,040 M 7 J I v i VALVE'MECHANISM FOR PRESSURE 1 V i .TOOLS 4 Edward W. Stevens, Detroit, lVIicln, assimilate Ghicago'Pneumatic Tool CompanypNewYork', N. Y., a corporationof New Jersey Application December 27, 1929 Serial No. 416,183 7 2 Claims. (01. 121 -19) 1. This invention relates to fluid pressure tools the closure for the other end-of the valve chant-' and, more. particularly to. improvements in the ber-may be integral withcase 9 or maybe provalvemechanism for the same. l vided by handle 7, in'the present instance it is One object of .theinvention is to provide ver a separate member or plate 11; D'dwels -9b '1 5'. simple and compact valve mechanism which will (Fig. "3) maintain case 9 and lid in Proper '60. permit the construction of compact toolshaving relation with cylinder 4. Mounted in the-valve rapid powerful action with low air consumption. chamber 9a with. its opposite edges in'ifr'ee slid Another object is to minimize the eifect of wear ing engagement with closures '10 and l'l -is aon .the valve parts and to reduce repair and resimple tubular valve 12 in'tl'le form of a narrow 9; placement expense to a negligible amount. Animperforate ring.- r a 1 t other object is to provide a small light valve with -All of the ports enteringthe valve chamber a .very short throw which valve can be cheaply -to affect or to-be affectedbythe position of valve made of any suitable or desired material and 12 are disposedin'cas'e 9-in the same transverse has only one surface requiring accurate machinplane. Motive fluid is admitted to the -valve= -1 ing. Other objects will be apparent from the dechamber by *an' annular series of -spaced=-p0rts tailed description which follows. .1 13, 14, 15an'd 16,- which constantly' subject the In order to illustrate the invention one conexterior of valve -12--to live' motive'fluid. These crete embodiment thereof .is shown in the acports compriseopposed pairs 13, 15 and14; 16. companying drawing in which: Y The short live air passages extending to ports iii; a. side elevational' view largely in 13' and 14 on oneside of the median line of s section through a pneumatic tool; the valve-chamber are much smaller than those Fig.2 is a fragmentary view showing the secleading to ports -l5 and; 16 on the other; side tioned portions of the tool of Fig. 1 with the so that when the valve is in the'position shown piston and valve in different positions the secin Figs; 2 and 3 amuch greaterxquantity of 2 tion being substantially on the line 2-2 of Fig. motive fluid is admitted to the pistonichambei 80. 3;, and V than when in the position shown'in Fig. 1. -Be-' Fig. 3 is a transverse sectlonalview. substantween .inlet ports 13 and '14 is outlet port 17- tially on the line 3-3 of Fig. 2. w A from which extends a passage 18 through cap-'- 7 While thelnvention is capable of general ap- 10 andaxially through the wall of cylinder 4" $0 plication to all fluid pressure tools. in which a to open into the forward end of the piston cham- I ;valve controls the reciprocations of another ber by a port 18a for motive fluid. to drive the member, the embodiment chosen for the purpiston on its rearward or non-working stroke. pose of illustration comprises a small hand tool Directly opposite outlet port 17 in valve case 9 of the type usually referred to as a chipping is another outlet port 19 intermediate inlets15 86 hammer. This tool has a cylinder 4 providing a and 16 which communicates with a short pas piston chamber 4a within which reciprocates sage 20 through cap 10 and opening directly into piston 5 to strike blows upon the shank of a the rear end of the piston chamber for motive working tool 6 insertedinto thefront end of the fluid to drive thepiston on its forward or workcylinder. The rear end of the cylinder is closed ing stroke. Since all of the ports in valve case by the usual throttle handle '7 having an exten- 9 opening into the valve chamber 9a are ansion 7a in threaded engagement with the ex-' nually disposed in the same plane, the moveterior of the cylinder and providing an inlet ment of motive fiuid from the inlet to the outlet passage 8 for motor fluid. is most free and direct. Valve 12 controls only In the tool shown the valve mechanism for the admission of motive fluid to piston chamber 45 controlling the movement of piston 5 is disposed 4a. The exhaust 'of motive fluid is controlled 109 within handle extension 7a. and clamped against; by piston 5 as it overruns ports 21a and 21b the end ofcylinder 4 providing a valve chamber which open into an axial passage 21 in cylinder 9a in line with piston chamber 4a. The valve 4 with vents directly to atmosphere.

chamber is formed by the bore of a ring-shaped The throw of the valve is efiected by a com- 50, valve case 9, which bore is substantially circular bination of line and built-up pressure on the but is elongated slightly ina direction transverse one side and a reduced pressure on the other. to the axis of the cylinder (Fig. 3). Clamped For example, in Fig. 1 the valve has just shifted between case 9 and cylinder 4 is a closure'memto the lower side to seal outlet port 19 comber or lid 10 forming a partition between the municating, with the rear piston chamber now 551 valve chamber and the piston chamber. While at reduced or atmospheric pressure by the un- 1 f: T covering of vent port 21b by piston 5, and to admit'motive fluid in the restricted quantity determined by the size of the live air passages to inlet ports 13 and 14 through passage 18v for driving piston 5 on its rearward stroke, When as it moves rearwardly. In consequence, the

valve shifts to the position shown; in Figs. 2

, and 3 whereupon live motive fluid in full volume determined by the large live airv passages leading to inlet ports 15 and 16v is immediately avail-' able in the rear end of the piston chamber, to reverse piston 5 for a powerful working stroke. Just before the blow is struck the'piston opens vent port 212; and seals port 21a with the'result that pressure falls in outlet'port 19 but is, built up in outlet port 17, thus causing the valve to shift again and complete the cycle.

I amawareof previously known forms of long tubular valves such as disclosed in, German Patents Nos. 217,428 and 218,081, also in British Patents 192,277, 208,961 and 210,662, but my invention is a distinct advance over these in that theparts are muchsimplified resulting in j the specific details thereof,

a much lighter and more compact-tool.v Still more, imPortantis the improved operation, the faster and more powerful blows, and the decreased air consumption. Without doubt, the small size and light weight of the ,valve, its short throw, and the novel arrangement of portings in the valve case with the balancing of pressures on the valve are contributing factors in securing the many advantages of this invention. I While the invention hasbeen herein disclosed in what is now considered to'be a preferred form, it isto be understood that it is notv limited to but, covers all changes, modifications and adaptations within the scope of the appended claims.

I claimas my invention:

1. A fluid pressure toolhaving a cylinder pro- I viding a piston chamber, apiston reciprocable therein, valve-mechanismfor automatically con trolling the distribution of motive fluid to. the opposite .ends of said chambercomprisinga thin cylindrical valve case providing a valve chamber in line with said piston chamber, a partition member interposed between said case and said cylinder, means including a port in said partition member providing a short and direct passage from said case to the rear end of said piston chamber, a closure for the end of said base opposite said partition member, a narrow imper- -forate ring valve in said valve chamber with its edges slidably engaging said partition member and said closure, means providing a reservoir of motive fluid extending completely around the periphery of said valve case, said valve case having pairs of radial inlet ports extending through opposed portions thereof and radial outlet ports between the inlet ports making up each of said pairs, all of said valve case portsv being in the same transverse plane and under control or said valve, one of said outlet ports connecting with said partition port. 2. A fluid pressure tool having a cylinder providing a piston chamber, a pistonreciprocable therein, valve mechanism for automatically con-,

trolling the distributionof motive fluid to'the opposite ends of saidchamber'comprising a'thin cylindrical valve case providing a valvechamher in line with said piston chamber, a partition member interposedbetween .said case'and said cylinder, means including. a port in said partition member. providing a short. and directpas-J sage from said case to the rear end of said piston chamber, a closure for the end of said-case op posite said partition member, a narrow-.imperfoev rate ring. valve in said valve chamber with its edges slidably engaging saidpartition member and said closure, said closurebeing secured to said cylinder for maintaining said valve mech-f anism parts in assembledrelation and providing a motive fluid chamber extending completely around the exterior of. said valve case, said valve casing havingpairsof radial inlet ports extending through opposed portions v thereof .and radial outlet, ports between the, inlet portsmaking up each of said. pairs,- all'of. said valve case ports being in the same transverse'plane and under control of said valve, one of :said outletports connecting with said partition port, and meansports tothe connecting the other :.of said outlet opposite end of saidipiston chamber. s w EDWARD,.W;.STEVENSz-' 

